System and method for establishing local control of a space conditioning load during a direct load control event

ABSTRACT

A system for establishing local control of a space conditioning load includes a switch for controlling a flow of energy for a space conditioning load. Control logic is operatively coupled to the switch, for receiving control parameters associated with a direct load control event from a utility provider. The control logic may also measure room temperature based on received temperature signals and determine if a room temperature is greater a comfort temperature range. The control logic may eliminate operation of a direct load control program if the room temperature is greater than or equal to the comfort temperature range. The control logic may log and signal back to the utility provider that the comfort temperature range is exceeded. The control logic may then restore local control of the switch and initiate a temperature setback control to a thermostat for the remainder of the control period.

BACKGROUND

Utility providers face the problem of satisfying consumer demand forelectrical energy during peak and off-peak demand periods. Totalelectrical energy demand varies significantly between the peak andoff-peak demand periods. For example, energy demand typically peaks on ahot summer afternoon as a result of the widespread simultaneousoperation of air conditioning systems, and energy demand subsequentlydrops during the off-peak period of the late evening. To accommodatevery high peak demands, utility providers face options of investing inadditional power generating capacity, buying power from other utilitieshaving excess capacity, or using an electrical load management system tocontrol the amount of electrical energy distributed over the electricaldistribution network during peak energy demand periods by electricalload reductions, commonly referred to as load shedding.

As of this writing, many utility providers have turned to load sheddingas the most viable option to address very high peak demands. Loadshedding usually comprises “direct load control” or demand responseprograms. Direct load control is a method where utility providers mayinterrupt the loads of their consumers during critical demand times.

In exchange for permitting this interruption, the consumer generallyreceives more favorable energy rates because that customer is notconsuming energy generated by the auxiliary or back-up devices of theutility provider which may be needed during very high peak energydemands.

As one example of load shedding, a homeowner on a direct load controlprogram may find his air conditioner periodically interrupted on hotsummer days by a switch operated by the utility provider. In exchangefor permitting this remote operation of the switch, the homeowner'sutility bill is generally lower than that of customers not on the directload control plan. Other incentives include home owner compensation inexchange for participating in the program. This load cycling by theutility provider may reduce overall energy consumption when electricitydemand is highest, thereby improving grid reliability and reducingenergy costs for the utility provider.

There are typically two methods used to reduce HVAC load in a demandresponse program: a cycling method and temperature set back. The cyclingmethod generally includes shutting off the compressor on a periodicbasis that reduces the normal run time of the compressor. This methodprovides the utility with a known and controllable load reduction sincethe amount of run time reduction is directly controllable by the commandissued.

A problem associated with the cycling method is that the indoortemperature will usually continually rise during the control event andthere is no temperature cap to limit this rise. Depending on how longthe control events lasts, on how well the home is insulated, and theoutdoor temperature, the indoor temperature may raise to a level that isuncomfortable for the customer. Customers may be more reluctant to signup for cycling programs if the temperature rise during the event is toohigh or unknown, thus driving up the cost for customer acquisition andresults in higher program costs.

A second method for load reduction is to perform a temperature setback.Utilities can send a setback value, say thirty-four degrees, to all thethermostats so that the HVAC is now regulating the indoor temperature ata higher value than what the customer has set it for. Every degree oftemperature setback usually results in some energy reduction from theHVAC system. This method may limit the indoor temperature rise—making iteasier to market to customers.

To address the cycling problem, utility providers often establishmaximum (cooling) and minimum (heating) temperature limits for the spacebeing serviced by the HVAC system. So for a cooling scenario in thesummer months, utility providers allow the load shedding program to beoverridden or suspended temporarily when the maximum temperature isreached. In this way, the HVAC system may be provided with power andstart operating again to cool the space coupled to the HVAC system. Theproblem with this solution is that the maximum and minimum temperaturelimits are set to be identical across all customers. Also, the directload control program may resume once the temperature of the space hasfallen below the maximum temperature.

Using identical maximum and minimum temperature limits across allcustomers by a utility provider does not account for differences in theconstruction of the various spaces of the customers being serviced. Forexample, a first building may be poorly insulated and may reach themaximum temperature on a hot day very quickly within an hour or two.Similarly, a second building may be well insulated but its spaceconditioning load may be improperly sized for the space.

Meanwhile, a third building may be well insulated and may have properlysized space conditioning load. In this situation, the third building maynot reach the maximum temperature on a hot day until several hours,significantly more than the first building with poor insulation and/or apoorly sized space conditioning load. A person residing in the firstbuilding will be less likely to subscribe to the direct load controlprogram of the utility provider since the first building will reach amaximum and uncomfortable temperature very quickly and frequently duringa operation of a direct load control program.

Another method to reduce customer discomfort is to allow the customer tooverride that event when the indoor temperature rises too high. Thisreduces the energy reduction that the utility is seeking.

Another solution that has been proposed to address the problemsassociated with cycling load control is to modify cycling within thedirect load control program and to resume normal cycling when a maximumor minimum temperature has been avoided. Cycling generally refers to aset period or length in time in which a space conditioning load isprovided with power and without power. For example, a first cycle mayhave a predetermined length of thirty minutes. During this thirty minutewindow, power for the space conditioning load may be stopped for thefirst twenty minutes of the window, while during the remaining tenminutes of the window, power may be supplied to the space conditioningload.

One solution that has been suggested to address the discomfort by aconsumer when a maximum temperature for a space has been reached on ahot day is to modify the first cycle noted above. The first cycle may bemodified so that there is less time in which power is not provided tothe space conditioning load. For example, the off-power time may beadjusted from twenty minutes to fifteen minutes so that power is nowsupplied to the space conditioning load for fifteen minutes instead ofthe lower value of ten minutes.

While this proposed solution of modifying cycling of a direct loadcontrol program may help a consumer to cool a space to avoid a maximumtemperature on a hot day, the proposed solution requires that the normalcycling be resumed once the maximum temperature is avoided. As notedabove, if a building is poorly insulated and/or it has an improperlysized space conditioning load, the consumer will likely experience themaximum temperature quickly and frequently while the direct load controlprogram is being executed. Indoor temperatures may swing wildly as thecycling value changes from the original to the modified program andback.

Accordingly, what is needed is a system and method that may overcome theproblems associated with conventional direct load control programs thatdo not account for differences that may exist across consumers withrespect to insulation and/or sizes for the space conditioning loads.What is needed is a system that allows a customer or utility to controla maximum temperature rise under a direct load control program. Anotherneed exists for a system that advises a utility provider on how manycustomers actually reached this maximum temperature rise to optimizetheir load control program.

SUMMARY OF THE DISCLOSURE

A method and system for establishing local control of a spaceconditioning load during a direct load control event issued by a utilityprovider are disclosed. The method includes receiving one or morecontrol parameters associated with the direct load control event andmeasuring room temperature of a climate controlled space. The methodfurther includes determining if the room temperature is one of greaterthan and equal to a comfort temperature range, then completely disablingdirect load control of the space conditioning load from the utilityprovider, logging and signaling back to the utility provider that thetemperature threshold is reached, and transitioning control to atemperature setback method.

A system for establishing local control of a space conditioning loadduring a direct load control event issued by a utility provider includesmeans for receiving one or more control parameters associated with thedirect load control event and means for measuring room temperature of aclimate controlled space. The system may also include means fordetermining if the room temperature is one of greater than and equal toa comfort temperature range and means for eliminating direct loadcontrol of the space conditioning load from the utility provider if theroom temperature is one of greater than and equal to a comforttemperature range. The system may send a signal signal back to theutility provider when the room temperature has exceeded the comforttemperature range. The system also has means for transitioning to atemperature setback control of the space conditioning load.

A system for establishing local control of a space conditioning load isalso described and it may include a switch for controlling a flow ofenergy. The system also has control logic operatively coupled to theswitch, for receiving one or more control parameters associated with adirect load control event from a communications network. The controllogic may also measure room temperature based on received temperaturesignals and determine if a room temperature is one of greater than andequal to a comfort temperature range. The control logic may eliminateoperation of a direct load control program associated with the one ormore control parameters received if the room temperature is one ofgreater than and equal to a comfort temperature range. The control logicmay then restore local control of the switch.

BRIEF DESCRIPTION OF THE DRAWINGS

In the Figures, like reference numerals refer to like parts throughoutthe various views unless otherwise indicated. For reference numeralswith letter character designations such as “102A” or “102B”, the lettercharacter designations may differentiate two like parts or elementspresent in the same figure. Letter character designations for referencenumerals may be omitted when it is intended that a reference numeral toencompass all parts having the same reference numeral in all Figures.

FIG. 1A is a diagram of a system for establishing local control during adirect load control program;

FIG. 1B is a front view of an exemplary display with a user interfacefor a customer premise control system that helps a consumer establishlocal control during a direct load control program;

FIG. 2 is a graph that includes plots of temperature versus time andpower supply versus time for a method and system that establish localcontrol during a direct load control program; and

FIG. 3 is a flowchart illustrating a method for establishing localcontrol during a direct load control program.

DETAILED DESCRIPTION

Referring initially to FIG. 1A, a diagram of a system 100 forestablishing local control during a direct load control program isillustrated. The system 100 may include a customer premise controlsystem 10, a space conditioning load 24, a climate controlled space 26,a wireless communications tower 28, a communications network 30, acontroller 32 at a utility provider, and a personal computing device 36.Exemplary wireless communication networks that may employ wirelesscommunications towers 28 or wireless environments in general include,but are not limited to, Advanced Metering Infrastructure (AMI) networks,Home Area Networks (HANs), any combination of the above, and othersimilar wireless communication networks. Many of the system elementsillustrated in FIG. 1A are coupled via communications links 103A-D tothe communications network 30.

The links 103 illustrated in FIG. 1A may comprise wired or wirelesslinks. Wireless links include, but are not limited to, radio-frequency(“RF”) links, infrared links, acoustic links, and other wirelessmediums. The communications network 30 may comprise a wide area network(“WAN”), a local area network (“LAN”), the Internet, a Public SwitchedTelephony Network (“PSTN”), a power lines communication (“PLC”) network,a paging network, or a combination thereof. The communications network30 may be established by broadcast RF transceiver towers 28. However,one of ordinary skill in the art recognizes that other types ofcommunication devices besides broadcast RF transceiver towers 28 areincluded within the scope of the invention for establishing thecommunications network 30.

The controller 32 at the utility provider may comprise a computer serverthat generates and stores various load control parameters 34 which aresent over the communications network 30 to the customer premise controlsystem 10. Such load control parameters 34 may include, but are notlimited to, the total duration of a utility cycling control event, atemperature delta value, and a duty cycle that defines the ratio ofpower removed from the space conditioning load and power provided to theconditioning load over a predefined period. These exemplary load controlparameters 34 will be discussed in further detail below in connectionwith FIG. 3.

The personal computing device 36 which is coupled to the communicationis network 30 may comprise a general purpose computer that may beoperated by a customer to issue commands to the customer premise controlsystem 10. Similarly, the personal computing device 36 may be operatedby a utility provider for issuing commands to the controller 32 at theutility provider. In this description, the personal computing device 36may include a cellular telephone, a pager, a PDA, a smartphone, anavigation device, a hand-held computer with a wireless connection orlink, a lap-top, a desk top, or any other similar computing device.

The customer premise control system 10 may comprise a transceiver 12, anantenna 26, load control logic 14, a switch 18, a thermostat andtemperature sensor 20, memory 16, and a display with a user interface22. The transceiver 12 may comprise a communication unit such as amodem, a network card, or any other type of coder/decoder (CODEC) forreceiving and sending load control signals to and from thecommunications network 30. In a wireless embodiment, the transceiver 12may further comprise a radiofrequency circuit for generatingradiofrequency communication signals which utilize the antenna 26 andthat establish the wireless communications link 103B. In otherembodiments, the transceiver 12 may be coupled to the communicationsnetwork 30 by a direct wired communications link 103C.

While the elements of the customer premise control system 10 have beenillustrated as contained within a single rectangular dashed box, one ofordinary skill in the art recognizes that any of these elements for thecustomer premise control system 10 may employ various differentelectronic packaging schemes without departing from the scope of theinvention. That is, for example, the transceiver 12 may reside in adifferent housing relative to the load control logic 14. Similarly, theload control logic 14 may reside in a housing which is separate relativeto the housing for the thermostat and temperature sensor 20. And lastly,all of the elements of the customer premise control system 10 may residewithin a single housing without departing from the scope of theinvention.

The load control logic 14 may comprise hardware or software or acombination thereof. The hardware may comprise a microprocessor runningvarious types of software. The hardware may include electronics, such asapplication specific integrated circuits (ASICs) and the like. The loadcontrol logic 14 receives and processes signals from the transceiver 12in order to control the switch 18 which supplies power to the spaceconditioning load 24.

The load control logic 14 and switch 18 may form a unit that is madesimilarly to the switch described in U.S. Pat. No. 5,462,225 issued inthe name of Massara et al., the entire contents of which are herebyincorporated by reference. However, the load control logic 14 and switch18 illustrated in FIG. 1A are not provided with any pre-set orpredetermined maximum and minimum space temperature limits prior toinstallation of the load control logic 14 and switch 18 at a customerpremises, as suggested by U.S. Pat. No. 5,462,225. The switch 18 isdesigned to control power supplied to the space conditioning load 24.

The load control logic 14 may comprise several timers: one for trackingload shed time; one for tracking load restore time; and one for trackingthe length of a utility cycling control event, as described below inconnection with FIGS. 2 and 3. The load control logic 14 allows theconsumer to completely disable and override any commands issued under adirect load control event. The load control logic 14 allows the consumerto establish a comfort temperature range or temperature delta value 56as described below in connection with FIG. 1B. In other exemplaryembodiments, the utility provider may also establish the comforttemperature range or temperature delta value 56. This comforttemperature range or temperature delta value 56 allows a consumer orutility to completely stop or disable a direct load control of and ifthe climate controlled space exceeds the temperature value establishedby the temperature delta value 56.

The temperature delta value 56 may be established relative to a currentroom temperature or relative to a temperature set point of thethermostat 20. One of ordinary skill the art recognizes that atemperature delta value 56 relative to a current or absolute roomtemperature may be different compared to a set point of the thermostat20. That is, one of ordinary skill in the art recognizes that atemperature set point of a thermostat 20 does not always reflect thecurrent room temperature of a climate controlled space 26.

The transceiver 12 is coupled to the load control logic 14. Thetransceiver 12 may relay the load control parameters 34 from thecontroller 32 at the utility provider to the load control logic 14. Theload control logic 14 may also transmit messages with the transceiver 12to the controller 32 at the utility provider as well as to the personalcomputing device 36 via the communications network 30.

The transceiver 12 and load control logic 14 may be part of the deviceknown as a digital control unit (DCU) manufactured by Comverge, Inc. TheDCU is designed to be coupled outside of a dwelling near one or moreparts of an HVAC system, such as near the compressor of anair-conditioning unit. The DCU may be used for communication throughvarious channels including through wide area and local area networks.Another example of the load control logic 14 is a computational devicelike a computer or dedicated processing unit that is coupled to thespace conditioning load 24.

The load control logic 14 may be coupled to memory 16. The memory 16 maycomprise a volatile component or a non-volatile component, or acombination thereof. The non-volatile component may comprise read onlymemory (ROM). The ROM may store the operating system (OS) for the loadcontrol logic 14 which may be executed by a central processing unitand/or firmware of the load control logic 14 as understood by one ofordinary skill in the art.

The volatile component for the memory 16 of the customer premise controlsystem 10 may comprise random access memory (RAM). The volatile memorycomponent for the customer premise control system 10 may incorporateother different memory technologies, such as, but not limited to,erasable programmable read-only memory (EPROM) or electrically erasableprogrammable read-only memory (EEPROM), and/or flash memory andferroelectric random access memory (FRAM).

The memory 16 may store the instructions corresponding to the methodillustrated in FIG. 3. The memory 16 may also record events detected bythe load control logic 14 such as, but not limited to, actions taken byload control logic 14, data generated by the thermostat 20, load controlparameters 34 transmitted by the controller 32 at the utility provider,and commands issued by the personal computing device 36 coupled to thecommunications network 30.

The load control logic 14 is also coupled to the thermostat 20. Thethermostat 20 may comprise a programmable or intelligent thermostat thatis usually positioned inside the climate controlled space 26. Exemplaryprogrammable or intelligent thermostats known as of this writing includethose manufactured by White Rogers or Honeywell. The temperature sensormay be implemented as a temperature measurement component, such as athermistor, which senses space temperatures and outputs temperaturesignals representing measured space temperatures within the climatecontrolled space 26.

The thermostat and temperature sensor 20 may comprise a display having auser interface 22. Such a display having a user interface 22 maycomprise a touch screen display such as a touch screen display generatedby a liquid crystal display (LCD) or a light emitting diode (LED)display. Instead of a touch screen display, the display may not supporttouch commands but may instead work with a separate physical userinterface such as a keypad, keyboard, and designated function buttons asunderstood by one of ordinary skill in the art. One exemplary embodimentof the display with user interface 22 is illustrated and described belowin connection with FIG. 1B.

The space conditioning load 24 is coupled to the switch 18 which is inturn coupled to the load control logic 14. The space conditioning load24 may comprise a heating, ventilating, air-conditioning (HVAC) systemas understood by one of ordinary skill in the art. If the spaceconditioning load 24 is an air-conditioning system, the switch 18restores distribution of electrical power to the compressor of the spaceconditioning load 24. Alternatively, if the space conditioning load 24is a forced air heating system or a heat pump, the switch 18 restoreselectrical power to either the fan of a furnace or the compressor of aheat pump.

The climate controlled space 26 may comprise any type of room or volumewithin a building which is fully closed off or partially closed offrelative to the outside. The climate controlled space 26 may comprise asingle room or a plurality of rooms joined together by an airventilation system.

Referring now to FIG. 1B, this figure is a front view of an exemplarydisplay 22A with a user interface 22B for a customer premise controlsystem 10 that helps a consumer establish local control during a directload control program. The exemplary display 22A may comprise a touchscreen display that includes a predefined area having a user interface22B. In the exemplary embodiment illustrated in FIG. 1B, the userinterface 22B comprises screen controls that are represented bygeometric shapes, such as arrowheads, which allow a user to selectvarious values by pressing the arrow heads for selecting values in adesired direction, such as up or down for temperature control. However,other types of user interfaces 22B are included within the scope of theinvention and may include, but are not limited to, keyboards, keypads,and function specific buttons as understood by one of ordinary skill theart.

The exemplary display 22A of FIG. 1B presents a current temperature 52that has an exemplary magnitude of 74° F.; a desired temperature 54having an exemplary magnitude of 72° F.; a comfort zone range ortemperature delta value 56 that has an exemplary magnitude of +3° F.;and an energy price value 58 that conveys to a user the energy priceduring the current load shed period expressed in kilowatts per hour.

The comfort zone range or temperature delta value 56 has been providedwith a thicker border to indicate that it is the value which can bepresently adjusted with the user interface 22B, or set by the utilityprovider in other exemplary embodiments. In other words, the comfortzone range or temperature delta value 56 may be adjusted up or down bythe consumer by pressing the arrow keys of the user interface 22B, orthe value 56 may be sent by the utility provider as part of the loadcontrol event command.

The comfort zone range or temperature delta value 56 corresponds to arange expressed in degrees Fahrenheit which may be selected by a user ofthe customer premise control system 10. This temperature range ortemperature delta value 56 is the maximum range relative to atemperature set point, which is the desired temperature 54, or relativeto a current temperature 52 of the thermostat 20 that a user will allowthe temperature of the climate controlled space 26 to reach while thespace conditioning load 24 is under a direct load control programprovided by the controller 32 at the utility provider.

So, in a hot weather example, the temperature delta value 56 is themaximum temperature that the consumer or utility provider will allow theclimate controlled space 26 to reach relative to the desired temperature54 (temperature set point of thermostat 20) before the control strategyis shifted from cycling control to a temperature setback control. It isnoted that if the temperature delta value 56 is set relative to thecurrent measured temperature 52 by the thermostat 20, then this wouldmean that the room temperature of the climate controlled space 26 wouldneed to hit the maximum temperature of 77° F. if the comfort zone ortemperature delta value 56 is set equal to 3° F. relative to the currenttemperature 52 listed as 74° F. in a hot weather example.

Similarly, in a cold weather example (which is a heating scenario),temperature delta or comfort zone temperature 56 is the lowesttemperature relative to the set point temperature 54 or the currenttemperature measured by the thermostat 20 that the consumer or utilitywill allow the climate controlled space 26 to reach before the controlstrategy is shifted from cycling control to a temperature setbackcontrol.

The energy price value 58 may be supplied to the thermostat 20 by thecontroller 32 at the utility provider. The energy price value 58 willremind the consumer of how much energy may cost the consumer if theconsumer desires to keep the climate controlled space 26 very close tothe desired temperature value 54 while disabling or stopping control ofthe direct load control commands issued by the controller 32 at theutility provider.

FIG. 2 is a graph 200 that includes a plot 200A of temperature versustime and a plot 200B of power supply versus time for a method and systemthat establish local control during a direct load control program.Looking at the first plot 200A, the controller 32 at the utilityprovider may issue load control parameters 34 of a load control eventthat has a first desired length 202. The load control event may have anexemplary length 202 or duration of four hours, however, othermagnitudes for a load control event are included within the scope of theinvention. In the exemplary scenario illustrated in FIG. 2, the intendedlength 202 for the cycling strategy is cut short, well before itsintended four hour length, after approximately one hour and fortyminutes as indicated by the length 204 of the cycling control periodwhich is beneath the length 202 for the load control event.

Adjacent to the length 204 of the cycling control period is a length 206corresponding to a local control or temperature setback control periodprovided to the thermostat 20. The plot 200A includes a first line 52representing the room temperature and a second line 54 representing thethermostat set point.

The first line 52 gradually rises from a room temperature of 72° F. to atemperature of 75° F. while the space conditioning load 24 is under adirect load control program that is illustrated by the second plot 200Bof FIG. 2. The second plot 200B illustrates an exemplary cyclingstrategy comprising thirty minute intervals. For each thirty minuteinterval, there is a load shed time 208 comprising a magnitude of twentyminutes and a restore time 210 comprising a magnitude of 10 minutes.

During the load shed time 208, the switch 18 is activated by the loadcontrol logic 14 such that energy or power is removed from the spaceconditioning load 24. Conversely, during the restore time 210, theswitch 18 is activated by the load control logic 14 such that energy orpower is supplied or provided to the space conditioning load 24 so thatthe temperature of the climate controlled space 26 may be adjusted. Oneof ordinary skill in the art will recognize that other magnitudes forthe load shed time 208, the restore time 210, and the length of theintervals of the load control event may be varied without departing fromthe scope of the invention.

The second plot 200B illustrates how temperature within the climatecontrolled space 26 may rise while a space conditioning load 24 is undercontrol of a direct load control event in a hot weather example.Specifically, during the first load shed time 208A, the temperaturewithin the climate controlled space 26 may rise from 72° F. to 73° F.After the first load shed time 208A, and during the first restore time210A, the temperature of the climate controlled space 26 may fall below73° F. since the space conditioning load 24 is allowed to cool theclimate controlled space 26.

However, during the second load shed time 208B, the temperature withinthe climate controlled space 26 may rise from 73° F. to 74° F. After thesecond load shed time 208B and during the second restore time 210B thetemperature of the climate controlled space 26 may be moved down from74° F., etc.

One of ordinary skill in the art will recognize that the slope of theroom temperature 52 may drastically increase for climate controlledspaces 26 in which the space conditioning load 24 is improperly sizedand/or if the climate controlled space 26 is not well insulated.

The second plot 200B illustrates that the fourth load shed time 308D iscut short since the temperature delta value 56 having a magnitude of 3°F. was reached when the room temperature 52 hit the temperature of 75°F. (which is 3° F. above the thermostat set point 54 of 72° F. asillustrated in FIG. 1B). The fourth load shed time 308D was cut shortsince the load control logic 14 was constantly comparing the temperaturedelta value 56 against the room temperature 52. When the load controllogic 14 determines that the temperature delta value 56 was reached,then the load control logic 14 disabled the remote control from thedirect load control program supplied by the controller 32 of the utilityprovider.

At point 211 along the room temperature plot 52, the load control logic14 canceled or completely disabled the direct load control program andreturned control of the space conditioning load 24 over to thethermostat 20. Also at point 211, the load control logic 14 changed theset point temperature 54 of the thermostat from 72° F. to 75° F., whichcorresponds to the desired values illustrated in the example of FIG. 1B.One of ordinary skill in the art will appreciate that logic should beimplemented to ensure that the transfer of control from cycling totemperature setback should not cause short-cycling of the compressor. Inaddition, the load control logic 14 send a signal comprising an activitylog back to the utility via the transceiver 12 that the temperaturethreshold is reached.

The remaining plot 54 of the room temperature from point 211 towards theright and towards point 213 reflects how the room temperature of theclimate controlled space 26 was adjusted while under control of thethermostat 20. After the load control event ends, at point 213, on thesecond plot 54 for the thermostat temperature set point, the loadcontrol logic 14 changes the value of the thermostat temperature setpoint 54 from a value of 75° F. to 72° F. One of ordinary skill in theart will appreciate that other units of measure beyond the English unitsof measure that are described herein may be utilized, such as the metricsystem and temperature in degrees Celsius, without departing from thescope of the invention.

With respect to the temperature set back control segment 205 of FIG. 2,one of ordinary skill the art recognizes that a thermostat 20 may beprovided with predetermined or factory-set algorithms built-in in orderto efficiently control room temperature of a climate controlled space.The thermostat 20 may anticipate rises and falls in room temperature andactivate the space conditioning load 24 appropriately in order to keepthe temperature of the climate controlled space 26 very close to thedesired temperature reflected in the set point temperature 54.

While the first plot 200A illustrates that the full energy savings froma direct load control program was not realized, the first plot 200A alsoillustrates a unique balance between energy conservation and promotingtemperature comfort for a consumer. That is, during the cycling controlsegment 204 of the first plot 200A which was produced by the direct loadcontrol program provided by the controller 32 at the utility provider, asignificant energy reduction was realized by the utility provider.Meanwhile, during the same segment 204, the consumer experienced sometemperature discomfort relative to the climate controlled space 26.

Then, during the second segment 206 of the first plot 200A, energysavings for the utility provider are marginal, however, the consumer isafforded with a limit on the temperature rise of the climate controlledspace 26. By using the thermostat as the temperature control mechanismand not the time-based algorithms of the load control logic 14, theindoor temperature becomes more well behaved and limited to thetemperature delta 56 during segment 206 of the first plot 200A. In viewof these two segments 204 and 206, energy savings for the utilityprovider are realized while temperature comfort for a consumer isprovided so that the consumer will be more willing to participate in adirect load control program offered by the utility provider.

In a particular aspect, one or more of the method steps described hereinmay be stored in the memory 16 as computer program instructions. Theseinstructions may be executed by the load control logic 14 and thermostat20 to perform the methods described herein. Further, a processor that ispart of the load control logic 14, the memory 16, the thermostat 20, ora combination thereof may serve as a means for executing one or more ofthe method steps described herein.

FIG. 3 is a flowchart illustrating a method 300 for establishing localcontrol during a direct load control program. Step 305 is the first stepof the method 300 for establishing local control during a direct loadcontrol program. In step 305 control parameters may be received by theload control logic 14 of the customer premise control system 10. Thecontrol parameters may comprise the load control parameters 34 issued bythe controller 32 at the utility provider. The load control parameters34 may comprise a length or duration of a load control event, thetemperature delta value 56, shed time 208, and restored time 210 set foreach period of the load control event.

In step 305, the load control logic 14 may receive the comfort zonerange or temperature delta value 56 via the user interface 22B asillustrated in FIG. 1B. The load control logic 14 may also receive thedesired temperature or temperature set point value 54 of the thermostat20 via the user interface 22B of FIG. 1B. Alternatively, or in additionto the user interface 22B, the load control logic 14 may receive any oneor all of these parameters from the consumer operating a personalcomputing device 36 which is coupled to the communications network 30.While the controller 32 at the utility provider may provide thetemperature delta value 56, according to a preferred exemplaryimplementation, the temperature delta value 56 may be set or establishedby the consumer using the user interface 22 the of FIG. 1B or a personalcomputing device 36 of FIG. 1A.

Next, in step 310 the thermostat and temperature sensor 20 may measurethe room temperature of the climate controlled space 26 and report thisdata to the load control logic 14. Alternatively, or in addition to, theload control logic 14 may ping or request temperature data from thethermostat and temperature sensor 20.

Subsequently, in decision step 315, the load control logic 14 maydetermine if the room temperature is greater than or equal to thetemperature delta value 56 that was received in step 305. If the inquiryto decision step 315 is negative, then the “No” branch is followed todecision step 320. One example of a negative inquiry is illustrated inFIG. 2 when the room temperature is at a value of 73° F. which is 2° F.below the temperature delta value 56 comprising 3° F. or 75° F.

If the inquiry to decision step 315 is positive, then the “Yes” branchis followed to step 355 in which the thermostat set point value 54 ischanged to the temperature delta value 56. A positive inquiry todecision step 315 is illustrated in FIG. 2 at point 211 on the roomtemperature plot 52. At point 211 in FIG. 2, the temperature of theclimate controlled space 26 reached 75° F. which is equal to the sum ofthe temperature delta value 56 added to the desired temperature value orcurrent temperature set point 54 of the thermostat 20.

In decision step 320, the load control logic 14 determines if theutility cycling control event having a duration 202 as measured by acycling control event timer is complete. If the inquiry to decision step320 is positive, then the “Yes” branch is followed to step 325 in whichthe load control logic 14 this enables the load cycling control event.The process then ends after step 325.

If the inquiry to decision step 320 is negative, then the “No” branch isfollowed to decision step 330. In decision step 330, the load controllogic 14 and specifically, a load shed timer, of the load control logic14 may determine if the load shed time 208 for the current load cyclehas expired. If the inquiry to decision step 330 is negative, then the“No” branch is followed to step 335 in which load shedding relative tothe space conditioning load 24 is continued. The process then returnsback to step 310 in which the room temperature is measured.

If the inquiry to decision step 330 is positive, then the “Yes” branchis followed to step 340 in which the control of the space conditioningload 24 is returned to the thermostat and temperature sensor 20. Anexample of a positive inquiry to decision step 330 exists in FIG. 2after the duration of the first shed time 208A. At the first point ofthe restore time 210A, control of the switch 18 is given back to thethermostat 20.

Next, in decision step 345, the load control logic 14 determines if thetimer for the restore time 210 has expired. Referring back to FIG. 2,the shed time 208 for each cycle or period of the example illustrated inthis Figure was set to twenty minutes while the restore time 210 foreach period or cycle was set to ten minutes. In decision step 345, theload control logic 14 determines if the ten minute duration set for therestore time 210 has expired for the example illustrated in FIG. 2.

If the inquiry to decision step 345 is negative, then the “No” branch isfollowed back to step 310 in which the room temperature is measured. Ifthe inquiry to decision step 345 is positive, then the “Yes” branch isfollowed to step 350 in which the load shed timer of the load controllogic 14 is reset or restarted. The process then proceeds back to step310 in which the room temperature is measured.

Referring now again to step 355, this step illustrates thermostat 20being set to the temperature delta value or comfort zone value 56 sincethe load control logic 14 determines that the room temperature is equalor greater to the temperature delta value 56 relative to either athermostat set point value 54 or the current room temperature 52 whenthe temperature delta value 56 was established. In other words, as notedpreviously, the temperature delta value or comfort zone range 56 may beset relative to a thermostat set point temperature 54 or relative to acurrent temperature of the climate controlled space 26. In a preferredand exemplary embodiment, usually the comfort zone temperature value ortemperature delta value 56 will be set relative to the temperature setpoint value 54.

As noted previously, step 355 corresponds to point 211 on the plot 52 ofthe room temperature in which the load control logic 14 changes thetemperature set point value 54 of the thermostat 20 to a new value basedon the comfort zone range or temperature delta value 56 by adding thetemperature delta value 56 to the original or first thermostat set pointtemperature 54. In the exemplary embodiment illustrated in FIG. 1B, thismeans that the thermostat temperature set point value 54 is changed from72° F. to 75° F. (which corresponds to the temperature delta value 56 of3° F. being added to the temperature set point value 54 having amagnitude of 72° F.).

Next, in step 357, the load control logic 14 may maintain a log that thetemperature threshold is reached, that the direct load control cyclingprogram is stopped, and that temperature setback mode is entered. In atwo-way system, the load control logic 14 in step may transmit a messageback to the utility via the transceiver 12 that the temperaturethreshold is reached.

Next, in step 360, the load control logic 14 disables the direct loadcontrol cycling program and its corresponding load control parameters 34that were transmitted to the load control logic 14 in step 305. Thisdisabling of the direct load control cycling program by the load controllogic 14 restores local control of the space conditioning load 24 to thethermostat 20.

Next, in step ???, the load control logic 14 logs that the temperaturethreshold is reached, direct load control cycling program is stopped andthat temperature setback mode is entered. In a two-way system, the loadcontrol logic 14 may transmit a message back to the utility via thetransceiver 12 that the temperature threshold is reached.

Subsequently, in decision step 365, the load control logic 14 determinesif the duration 202 of the load cycling control event is complete. Ifthe inquiry to decision step 365 is negative, then the “No” branch isfollowed back to step 360. If the inquiry to decision step 365 ispositive, then the “Yes” branch is followed to step 370 in which theload control logic 14 restores the thermostat temperature set pointvalue 54 back to its initial value. In the exemplary embodimentillustrated in FIG. 2, this means that the load control logic 14 changesthe current thermostat temperature set point value 54 of 75° F. to 72°F. as illustrated by point 213 of the plot 52 of room temperature inFIG. 2. The process 300 then ends.

The word “exemplary” is used in this description to mean “serving as anexample, instance, or illustration.” Any aspect described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects.

In this description, the term “application” may also include fileshaving executable content, such as: object code, scripts, byte code,markup language files, and patches. In addition, an “application”referred to herein, may also include files that are not executable innature, such as documents that may need to be opened or other data filesthat need to be accessed.

The term “content” may also include files having executable content,such as: object code, scripts, byte code, markup language files, andpatches. In addition, “content” referred to herein, may also includefiles that are not executable in nature, such as documents that may needto be opened or other data files that need to be accessed.

As used in this description, the terms “component,” “database,”“module,” “system,” and the like are intended to refer to acomputer-related entity, either hardware, firmware, a combination ofhardware and software, software, or software in execution. For example,a component may be, but is not limited to being, a process running on aprocessor, a processor, an object, an executable, a thread of execution,a program, and/or a computer. By way of illustration, both anapplication running on a computing device and the computing device maybe a component. One or more components may reside within a processand/or thread of execution, and a component may be localized on onecomputer and/or distributed between two or more computers. In addition,these components may execute from various computer readable media havingvarious data structures stored thereon. The components may communicateby way of local and/or remote processes such as in accordance with asignal having one or more data packets (e.g., data from one componentinteracting with another component in a local system, distributedsystem, and/or across a network such as the Internet with other systemsby way of the signal).

In this description, a personal computing device may include a cellulartelephone, a pager, a PDA, a smart phone, a navigation device, or ahand-held computer with a wireless connection or link.

Further, certain steps in the processes or process flows described inthis specification naturally precede others for the invention tofunction as described. However, the invention is not limited to theorder of the steps described if such order or sequence does not alterthe functionality of the invention. That is, it is recognized that somesteps may performed before, after, or parallel (substantiallysimultaneously with) other steps without departing from the scope andspirit of the invention. In some instances, certain steps may be omittedor not performed without departing from the invention. Further, wordssuch as “thereafter”, “then”, “next”, etc. are not intended to limit theorder of the steps. These words are simply used to guide the readerthrough the description of the exemplary method.

Additionally, one of ordinary skill in programming is able to writecomputer code or identify appropriate hardware and/or circuits toimplement the disclosed invention without difficulty based on the flowcharts and associated description in this specification, for example.

Therefore, disclosure of a particular set of program code instructionsor detailed hardware devices is not considered necessary for an adequateunderstanding of how to make and use the invention. The inventivefunctionality of the claimed computer implemented processes is explainedin more detail in the above description and in conjunction with theFigures which may illustrate various process flows.

In one or more exemplary aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted as one or more instructions or code on a tangiblecomputer-readable medium. Computer-readable media include both tangiblecomputer storage media and tangible communication media including anytangible medium that facilitates transfer of a computer program from oneplace to another. A tangible computer storage media may be any availabletangible media that may be accessed by a computer. By way of example,and not limitation, such tangible computer-readable media may compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other tangible mediumthat may be used to carry or store desired program code in the form ofinstructions or data structures and that may be accessed by a computer.

Also, any connection is properly termed a tangible computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (“DSL”), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, and DSL are included in the definition ofmedium.

Disk and disc, as used herein, includes compact disc (“CD”), laser disc,optical disc, digital versatile disc (“DVD”), floppy disk and blu-raydisc where disks usually reproduce data magnetically, while discsreproduce data optically with lasers. Combinations of the above shouldalso be included within the scope of computer-readable media.

Although selected aspects have been illustrated and described in detail,it will be understood that various substitutions and alterations may bemade therein without departing from the spirit and scope of the presentinvention, as defined by the following claims.

What is claimed is:
 1. A method for establishing local control of aspace conditioning load during a direct load control event issued by autility provider, comprising: receiving one or more control parametersassociated with the direct load control event; measuring roomtemperature of a climate controlled space; determining if the roomtemperature is one of greater than and equal to a comfort temperaturerange; if the room temperature is one of greater than and equal to acomfort temperature range, then completely disabling direct load controlof the space conditioning load from the utility provider; andtransitioning control of the space conditioning load using a temperaturesetback method.
 2. The method of claim 1, wherein the one or morecontrol parameters comprise at least one of a duration for the directload control event, parameters associating with cycling a spaceconditioning load, load shed time, and load restore time.
 3. The methodof claim 1, wherein restoring local control of the space conditioningload comprises providing control to a thermostat.
 4. The method of claim1, further comprising receiving a comfort temperature range with a userinterface.
 5. The method of claim 4, wherein the user interfacecomprises one of a touch screen display, a key pad, a key board, and abutton.
 6. The method of claim 1, wherein the comfort temperature rangecomprises a threshold set relative to a temperature set point of athermostat.
 7. The method of claim 1, wherein the space conditioningload comprises at least one of an air conditioner and a furnace.
 8. Asystem for establishing local control of a space conditioning loadduring a direct load control event issued by a utility provider,comprising: means for receiving one or more control parametersassociated with the direct load control event; means for measuring roomtemperature of a climate controlled space; means for determining if theroom temperature is one of greater than and equal to a comforttemperature range; means for eliminating direct load control of thespace conditioning load from the utility provider if the roomtemperature is one of greater than and equal to a comfort temperaturerange; means for transitioning control of the space conditioning loadusing a temperature setback method; and means for logging and signalingto the utility provider that the temperature threshold is reached. 9.The system of claim 8, wherein the one or more control parameterscomprise at least one of a duration for the direct load control event,parameters associating with cycling a space conditioning load, load shedtime, and load restore time.
 10. The system of claim 8, wherein themeans for restoring local control of space conditioning load furthercomprises means for providing control to a thermostat.
 11. The system ofclaim 8, further comprising means for receiving a comfort temperaturerange.
 12. The system of claim 8, wherein the means for receiving thecomfort temperature range comprises a user interface that comprises oneof a touch screen display, a key pad, a key board, and a button.
 13. Thesystem of claim 8, wherein the comfort temperature range comprises amagnitude set relative to a temperature set point of a thermostat. 14.The system of claim 8, wherein the space conditioning load comprises atleast one of an air conditioner and a furnace.
 15. A system forestablishing local control of a space conditioning load, comprising: aswitch for controlling a flow of energy; control logic operativelycoupled to the switch, for receiving one or more control parametersassociated with a direct load control event from a communicationsnetwork, for measuring a room temperature based on received temperaturesignals, for determining if the room temperature is one of greater thanand equal to a comfort temperature range, for eliminating operation of adirect load control program associated with the one or more controlparameters received if the room temperature is one of greater than andequal to a comfort temperature range, generating a signal indicatingthat the temperature threshold is reached, and for restoring localcontrol of the switch if the room temperature is one of greater than andequal to a comfort temperature range.
 16. The system of claim 15,further comprising memory for storing instructions and the one or morecontrol parameters.
 17. The system of claim 16, wherein the memorycomprises one of a volatile component and a non-volatile component. 18.The system of claim 15, further comprising a thermostat coupled to thecontrol logic.
 19. The system of claim 15, further comprising a display.20. The system of claim 15, wherein the control logic receives thecomfort temperature range from a user interface coupled to the controllogic.